The present invention relates to an apparatus for detecting a steering angle and an anglar velocity of a steering wheel in a vehicle, and more particularly to a steering sensor for detecting a steering angle and an angular velocity of a steering member.
Heretofore, an apparatus for detecting a steering angle and a angular velocity of a steering member generally included a disc mounted on a steering shaft, and a sensor secured to a steering column tube. The disc is designed to be rotated with the steering shaft, and has a number of small holes which are concentrically located thereon. The sensor has a luminescent element and a light receiving element, which are oppositely located on different axial sides of the disc and are positioned such that light emitted can pass through the holes of the disc and contact the light receiving element. When the steering shaft rotates by a driver's operation, the disc is forced to rotate with the steering shaft. In this condition, the light transmitted from the luminescent element to the light receiving element is interrupted by the rotation of the disc. The degree of the interruption is proportional to the number of rotations of the disc. The degree of the interruption is converted to an electric pulse, and thereafter the steering angle and the steering angular velocity are calculated by the electric pulse. Applicant has also proposed an invention relating to the detailed structure of the sensor and the disc in a separate application.
Known sensors for detecting a steering angle and a steering angular velocity, have been mounted on a gear box or a bearing wheel. This mounting results in the following disadvantages:
(a) It is difficult to assemble accurately the sensor because of the small space provided for mounting the sensor on a gear box or a bearing wheel; PA1 (b) It is difficult to maintain an accurate determination of the amount of revolution of the steering member after an absorbtion of impact energy generated from a collision which has occurred; PA1 (c) If the steering mechanism includes a tilting device, the accuracy of the sensor cannot be maintained while utilizing the tilting device. PA1 (d) It is troublesome to operate a steering wheel; and PA1 (e) Some type of cover must be provided for protecting the sensor from stones, dust or water.